THE EFFECT OF NITROGEN NUTRITION ON THE PROTEIN AND NON-PROTEIN NITROGEN OF WHEAT

Abstract

Wheat plants were grown in water cultures varied only with respect to nitrogen. The nitrogen as nitrate was supplied to half the plants continuously to maturity, and to the others only until the time of heading. Though uptake and reduction of nitrate continued in the former for some time after heading, organic nitrogen produced in vegetative parts of the plant after heading was not synthesized to protein but accumulated in the form of non-protein compounds. Regardless of the extent of the nitrogen reserves in vegetative parts, translocation to the kernels during filling took place in about the same proportion. In plants with limited nitrogen supply, translocation to kernels consisted largely of decomposed proteins, and the kernels contained less gluten nitrogen than those of the plants with unlimited nitrogen supply which drew upon both protein and non-protein reserves. The nitrogen fractions of the gluten proteins were unaffected by the nitrogen nutrition of the plants. The total amount of non-gluten nitrogen was apparently also unaffected by the nutrition. Amide nitrogen was the most labile of the nitrogen fractions used.